Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

The description discloses that page content is not stored, which is useful behavioral context. However, it does not mention whether the URL is fetched, what side effects occur, or how errors are handled, leaving important behavioral aspects unclear.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The description is concise and front-loaded, clearly stating the primary behavior in the first sentence and adding a brief non-storage note in the second. There is no unnecessary wording.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Given the nine optional parameters and no output schema, the description is incomplete. It does not explain the expected request shape, which parameters are relevant, what the returned host/scheme/status values look like, or how the unrelated schema fields fit into the tool's behavior.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

While the schema has descriptions for all parameters, the tool description only adds meaning for 'url'. Several parameters like city, zone, query, and ref appear unrelated to the stated purpose, and the description does not clarify how or when they should be used.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific outcome: return host, scheme, and HTTP status for a URL. It is mostly clear, but the broad optional schema with unrelated fields like city, zone, and query muddies the tool's actual purpose.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

The description does not explain when to use this tool versus siblings like fetch-status, normalize-url, or web-fetch. The only hint is 'Page content is not stored', which implies a metadata-only use, but no explicit guidance or alternatives are given.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.